Blow is used as an imprecation (often because it is less offensive than what would be considered swearing). Sense 29 from the OED provides some interesting examples:
- Used in imprecations: To curse, ‘confound’, ‘hang’. vulgar. (The pa. pple. is blowed.) Also with the implication of ignoring or
disregarding; blow!: used absol. as an exclamation of anger or
vexation; blow me tight! (cf. sense 22).
1781 G. Parker View Society & Manners I. 48 Blow me up (says he)
if I have had a fellow with such rum toggys cross my company these
many a day.
1819 T. Moore Tom Crib's Memorial to Congress 46 Says Bill,
‘there's nothing like a Bull: And blow me tight.’
1821 P. Egan Life in London iii. 225 Blow me tight if ever I saw
such a thing in my life before.
1827 J. Wight More Mornings at Bow St. 55 Blow me if I do!
1836 Dickens Sketches by Boz 2nd Ser. 184 The said Thomas
Sludberry repeated the aforesaid expression, ‘You be blowed’.
1840 F. Marryat Olla Podrida III. 20 If I do, blow me!
1859 Dickens Tale of Two Cities ii. i. 36 One blowed thing and
1865 Dickens Our Mutual Friend II. iv. xv. 287 Blowed if I
shouldn't have left out lakes.
1871 Blackwood's Edinb. Mag. May 551/2 Oh, blow it, governor.
1881 Daily Tel. 28 Jan. ‘Isn't it rather risky?’ I asked. ‘Blow
risks,’ he answered.
1882 J. A. Lees & W. J. Clutterbuck Three in Norway xxiv. 207
Retributive justice be blowed!
1922 F. Hamilton P. J.: Secret Service Boy ii. 70 I'm absolutely
blowed if I know what to do.
1922 F. Hamilton P. J.: Secret Service Boy ii. 84 Oh, blow! And I
go back to school in ten days.
1933 P. MacDonald Myst. Dead Police i. 6 ‘Blow me tight!’ said
Sergeant Guilfoil. For things were certainly happening in Farnley.
1957 I. Cross God Boy (1958) xv. 124 Then blow me if Dr
Hutchinson..didn't come padding round the post office corner.
1963 Listener 28 Mar. 540/1 It is no longer proper to use as our
second national motto in education ‘Blow you, Jack, our top five per
cent. are absolutely splendid’.